GROWTH IN STRAINS OF GILTHEAD SEABREAM SPARUS-AURATA L

Five independent data sets were analyzed to assess whether growth and survival differ among different strains of gilthead seabream, Sparus a urata, under captive culture conditions. Differences were detected and we deduced (a) inferior performance of a wild strain relative to a ha tchery strain; (b) lack of evidence for substantial heterosis in our p articular strains; (c) a slight trend among the larger fish to undergo sex reversal from male to female, and that sex effects should be cons idered in future growth analyses. There were no detectable detrimental effects of PIT (passive integrated transponders) tagging on a range o f S. aurata size classes.